Differing relations to early atherosclerosis between vitamin C from supplements vs. food in the Los Angeles atherosclerosis study: A Prospective Cohort Study

• Type of Material: Article
• Authors: Megha Agarwal, Cedars-Sinai Medical Center; Puja Kiran Mehta, Emory University; James H. Dwyer, University of Southern California; Kathleen M. Dwyer, University of Southern California; Anne M. Shircore, University of Southern California; Cheryl K. Nordstrom, Wayne State University; Ping Sun, University of Southern California; Maura Paul-Labrador, University of Southern California; Yuching Yang, Cedars-Sinai Medical Center; C. Noel Bairey Merz, Cedars-Sinai Medical Center
• Language: English
• Date: 2012-12-18
• Publisher: Bentham Open
• Publication Version: Final Published Version
• Copyright Statement: © Agarwal et al.
• License: Creative Commons Attribution-Noncommercial 3.0 Unported
• Final Published Version (URL): http://dx.doi.org/10.2174/1874192401206010113
• Title of Journal or Parent Work: Open Cardiovascular Medicine Journal
• ISSN: 1874-1924
• Volume: 6
• Issue: 1
• Start Page: 113
• End Page: 121
• Keywords: atherosclerosis; Ascorbic acid; cardiovascular disease.; vitamin C
• Research Categories: Health Sciences, Medicine and Surgery

Abstract

Objective: To determine the relationship of vitamin c intake from supplements vs food on early atherosclerosis detected by carotid intima media thickness (IMT). Background: Oxidative stress and endothelial dysfunction play a critical role in the pathogenesis of atherosclerosis. Die-tary vitamin C appears to have anti-oxidant properties and beneficial relations to endothelial function, yet vitamin C taken as a vitamin supplement does not appear to protect from cardiovascular events. The impact of vitamin c intake from sup-plements vs food on progression of atherosclerosis is unknown. Methods: We examined 3-year progression of carotid IMT in a randomly sampled cohort of 573 healthy women and men aged 40-60 years. Progression of carotid IMT was determined bilaterally with B-mode ultrasound at 3 examinations (1.5-year intervals). Intake of dietary vitamin C was measured by six, 24-hour recall interviews. Intake of vitamin C from vi-tamin supplements was measured by questionnaire in quartiles of supplement intake and no supplement. Vitamin C was-measured in plasma as ascorbic acid. Results: Carotid IMT progressed 10.0±16.5 μm/year (mean±SD) among all those with follow-up (n=500; 87%). For those who took vitamin C supplements, carotid IMT progression increased with dose (p-trend=0.0009). Among persons in the highest quartile (857-5000 mg/day) of vitamin C supplement intake compared to those not consuming any vitamin C sup-plements, carotid IMT progression increased three-fold (20.3±2.6 versus 7.6±1.8 μm/year (mean±SD); p<0.001). The ad-verse association of vitamin C supplement intake with carotid IMT was two-fold greater in the upper tertile of serum cho-lesterol compared to the lower two tertiles (p=0.01). In contrast to the adverse association of vitamin C supplements, vi-tamin C intake from food had a weak protective relationship on carotid IMT progression (reduced progression -5.0±1.9 μm/year; p=0.008). Conclusions: Vitamin C supplementation is associated with accelerated early atherosclerosis measured by carotid IMT compared to a protective association with vitamin C from food. Theadverse association of vitamin C supplementation may be greater in patients with higher serum cholesterol levels. The current results provide a potential mechanistic understand-ing for the observed differences between Vitamin C in supplements vs food in prior studies. Given these observa-tions,vitamin C supplementation does not appear to be currently advisable for prevention or treatment of atherosclerosis.